Double hung and single hung windows are comprised of two window sashes mounted in adjacent parallel window frame tracks. Single hung windows typically have the upper sash fixed while the lower sash is moveable in the vertical axis. Double hung windows typically have top and bottom sashes that are both moveable in the vertical axis. Traditional double and single hung windows typically used nailed in-place wooden stops to hold the sash into the window frame. As such, washing of the outside of traditional double and single hung windows must generally be done from the outside of the building, due to the difficulty and possible damage of removing sash stops to allow sash removal. In many instances, a storm/screen window has to be removed prior to washing the window exterior. Windows located above ground level also require the use of a ladder to reach the units making it more difficult and inconvenient to perform exterior cleaning.
With the evolution of the double and single hung window, the fixed wooden stops holding the sash into the frame were replaced by metal or plastic compression jamb liners containing the sash balance systems and slide track. The jamb liners allowed improved ease of sash removal, allowing the window sash to be washed on both sides from the inside of house. Removal of the sash from the jamb liner system usually required considerable physical strength, which made sash removal difficult or impossible for many people to clean the entire window. Further refinement of the hung window resulted in the tiltable sash which allowed cleaning of both sides of the sash with minimal physical effort to tilt the sash into the interior of the house.
Early tilting sash single and double hung windows incorporated tilt locks on the top corners of each operating sash and tilt pins at the bottom corners of the sash which engaged the jamb track to hold the sash into the frame. The evolution of the tilt single and double hung window has changed how the lock and tilt lock mechanism operates, but adhered to the basic tilt lock and tilt pin concept. Most of the evolved lock and latch systems became more complicated and as a consequent more expensive.
“Sash lock” or “sweep lock” is the common name of a cam lock mounted on an upper rail or check rail of a lower sash to lock the lower sash to a fixed or movable upper sash in a window. Sash or sweep locks can be used in pairs spaced toward the sides of window sash to interlock the check rails of a pair of closed sash. Check rails are the lower horizontal element of the upper sash and the upper horizontal element of the lower sash which interface together when a double hung window is in the closed position. When locked, sweep locks prevent either sash from moving toward an open position and also strengthen the wind resistance of the closed sash.
“Tilt lock” or “tilt latch” is the common name of a latch or lock that keeps a tiltable sash in an upright position for traveling vertically between open and closed positions within a window jamb. Ordinarily, a pair of tilt locks are arranged at stile edges of a lower sash to latch into vertical slots in a window jamb where the tilt locks prevent a lower sash from tilting until the tilt locks are manually unlocked.
Since sweep locks and tilt locks are both mounted on an upper rail of a lower sash, there have been several suggestions in the patent literature that these devices be combined. See for example U.S. Pat. Nos. 1,120,186; 5,090,750; 5,244,238; 5,398,447; and 5,791,700. These suggestions suffer from disadvantages.
Latches in which both sash locking and tilt locking are controlled with one lever can have difficulty providing smooth, consistent and reliable operation over their expected useful life. One disadvantage with single lever type latches is the possible accidental tilting of the sash when unlocking the unit. Another disadvantage of some latches is the poor adjustability of the lock/latch connections. Improvements in combined sash and tilt lock mechanisms are desired.